Indoor power distribution equipment such as medium voltage circuit breakers, switches, dry-type distribution and small power transformers, and the like, are known in the art. When the equipment is intended for placement outdoors, it is common to house such equipment in specialized metal enclosures for the purposes of protecting the equipment from environmental conditions—e.g., from rain and snow. Arc flash events can occur in such power equipment during normal operation, system transients, or during maintenance. When an electric arc occurs within the enclosure, it results in a pronounced increase in the pressure and temperature of gas within the enclosure. This sudden increase in gas pressure and temperature poses a risk of hot gas escaping the enclosure in an uncontrolled manner, which in turn poses a risk of harm to people or equipment in the vicinity. It is therefore desirable to minimize such risk, and in a manner that maintains protection of the indoor power equipment from outdoor environmental condition such as rain and snow.